1. Field of the Invention
The instant disclosure relates to a display backlight module and a method for manufacturing the same, in particular, to the backlight module disposed with a multi-layer reflective film with a feature of adjustable wavelength range of a light.
2. Description of Related Art
The backlight module applied to a liquid crystal display (LCD) panel is generally classified into two backlight types, preferably are an edge-type backlight and a direct-type backlight.
Refer to FIG. 1, an edge-type backlight module is shown. The light source is disposed on one side of the panel and preferably implemented as a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED). This edge-type backlight module is disposed below a liquid crystal display panel 101. The backlight module generally includes a prism plate 102 for advancing light diffusion. The backlight module also has a diffusion film 103 for averaging the outgoing light. The backlight module further includes a wedged-type light-guide plate 104. The light source 105 is disposed on one side of the light-guide plate 104. Below the backlight module, a light-reflecting plate 106 is disposed to reflect the downward light and guide to the panel.
The light is emitted from the light source 105. The emitting light may be fully distributed over the display panel from the light-guide plate 104. The downward light may be reflected and enter the panel by the light-reflecting plate 106. The upward light can be uniformed through an optical system assembled with a diffusion film 103 and a prism plate 102. The diffusion film 103 may minimize the uneven problem caused by the interference. Therefore, the backlight module provides a uniform light to the liquid crystal display panel 101.
The mentioned optical components are such as diffusion film 103 and light-guide plate 104. By implanting some diffusing particles or any related structure inside or on the surface of the optical components, the incident light may be disorderly to implement uniform light through reflections and refractions.
FIG. 2 further shows a schematic diagram of the conventional direct-type backlight module. The direct-type backlight module is implemented by disposing the CCFLs or LEDs underneath the liquid crystal display panel 201. The direct-type backlight module also includes a prism plate 202 for advancing the light diffusion, and a diffusion film 203 for averaging the outgoing light. The backlight module further includes a light source 205 and a lamp box 204 having a light-reflecting structure 206.
Other than the edge-type backlight module, the direct-type may project the light into the liquid crystal display panel 201 directly. For acquiring an even light source, the mentioned optical components such as prism plate and diffusion film are requisite. Further, some diffusing particles or structure may be implanted into the structure.
The mentioned optical components of the conventional backlight module may be referred to the optical module used in the display disclosed in U.S. Pat. No. 7,763,331. The related diagram is shown in FIG. 3.
An LCD device 30 is shown in the diagram. A liquid crystal panel 301 and its underneath backlight optical module are shown. The optical module includes an optical film 303, a brightness-enhancement film 305, a light-guide plate 307, and a lateral light source 308. A light-reflecting plate 309 for reflecting the downward light is also included below the light-guide plate 307.
The optical film 303 may be a diffusion film, a reflective polarized film, or a brightness-enhancement film. The brightness-enhancement film may be implemented to enhance the brightness with a structural design, a polarized light recycling means, or both of them. In the instant example, the brightness-enhancement film 305 is disposed between the light-guide plate 307 and the liquid crystal panel 301. In general, the polarizing films may be disposed on both sides of the liquid crystal panel 301. The light may be consumed as passing through the optical film 303, the light-guide plate 307 and the polarizing film. Some conventional solutions are provided through a multi-layer reflective polarizer preferably formed of the brightness-enhancement film 305 (e.g., DBEF, cholesteric liquid crystal), metal wire grid brightness-enhancement film, and prismatic brightness enhancement film to improve the brightness of backlight, and to minimize energy consumption.